Thermal relay and cut-out



Patented Nov. 1, 1932 UNETED STATES PATENT QFFECE XV. OKEEFFE, OFI/IIL'ION, MASSACHUSETTS, ASSIGNOR TO CONDIT ELECTRICALMANUFAC'lUl'ZING- CORPORATION, OF SOUTH BOSTON, DIASSACHUSETTS, A CORPO-RATION OF MASSACHUSETTS THERMAL RELAY AND CUT-OUT Application filedFebruary 17, 1930.

This invention relates to thermal cut-outs or relays of the type havingan electrically heated fusible elementwhich operates to control anauxiliary electric circuit, which, usually, is the pilot circuit of anelectrically operated circuit interrupter, and a heating element whichis included in the circuit to be protected for heating the fusibleelement.

One of the objects of the present invenion is the provision of a thermalcut-out or relay wherein the fusible element is located alongside and isclosely adjacent the heating element.

Another object of the invent-ion is the provision of a thermal cut-outin a tubular insulating casing having end terminals between which aheating element is connected and an intermediate terminal between whichand one end terminal a fusible element is removably connected.

A further object is the provision of a thermal cut-out of the type aboveset forth having simple and improved means by which the fusible elementcan be removed after it has operated; and specifically a cut-out havingan enclosing tubular shell through which aheating element is extendedand having a fusible element provided with attaching portions disposedadjacent the surface of the casing shell where they are readilyaccessible and an offset heat-absorbing portion that is locatedsubstantially in the longitudinal axis of the casing alongside theheating element.

In the usual thermal cut-out it is necessary to practically completelydismantle the device in order to replace the fusible element, and itconstitutes another object of this invention to provide a cut-outwherein the fusihle element is accessible through the side wall of thecasing shell by the removal of one terminal cap and without otherwisedisturbing the assembly of the cut-out.

A still further object is the provision of a thermal cut-out having afusible element and a heating element for heating the fusible elementeither of which can be replaced Without disturbing the other.

A yet further object is generally to improve the construction andoperation of ther- Serial No. 428,911.

mal cut-outs and relays for the control of electrically operatedswitches.

Fig. 1 is a plan view, partly in section, of a cut-out embodying theinvention.

Fig. 2 is a view similar to Fig. 1 showing an end cap partly removed.

Fig. 3 is a longitudinal sectional elevation of the cut-out of Fig. 1.

Fig. 4: is a section on line 44 of Fi 3.

Fig. 5 is a section on line 5-5 of Fig. 3.

6 is a perspective view of the inner insulating and terminal supportingtube.

F 7 is an end view of a terminal washer.

Fig. 8 is a perspective view of the fusible element.

Fig. 9 is an elevation showing a modified construction for the heatingand fusible elements.

Fig. 10 is an end view of a terminal Washer for the modification shownin Fig. 8.

Fig. 11 is a single phase wiring diagram showing the cut-out of theinvention associated with the pilot circuit of an electrically operatedswitch.

[is herein shown, the thermal cut-out or relay embodying the inventionincludes an inner tubular shell 10 of insulating material which hasexteriorly threaded terminal ferrules 12 and T l permanently fixed onits opposits ends by means of rivets 16 which pass through said ferrulesand tubular member. Internally screw threaded terminal caps 18 and 20are removably screw threaded on said i 'ules 12 and 14 respectively andconstitute the line terminals of the cut-out. As shown most clearly inFig. 6, the inner tubular shell 10 is formed with a longitudinal slot 22in its upper wall which extends substantially along the length of thetube and which terminates in the shoulder 24. An intermediate terminalmember comprising a metal ring 26 closely surrounds the tube 10 and hasa U-shaped inwardly directed peripheral portion 28 that is adapted to bereceived closely within the end of the slot 22 of said insulating tube10 adjacent the shoulder thereof. The bottom of said U-shapcd portion 28constitutes a flat terminal seat 30 which is provided with an attachingscrew 32 by means of which one end of the fusible element hereinafter tobe de In assembling the cutout, the end ferrule 12 is first riveted tothe insulating tube 10 after which the spacing ring 34, the intermediateterminal 26, and the outer tubular casing 72 are placed in position onthe inner tube 10. T 1e terminal ferrule 14. and the terminal block 38are then secured in position on the tube 10 by means of rivet 16. Theassembly of the heating element is obvious. The fusible element isplaced in position, after the outer casing 72 has been rotated touncover the slot 22 in the inner tube 10, by slipping one end thereofunder the annular end portion 78 of the outer casing and securing it bythe terminal screws 42 and 32 to its respective terminal seats. Theheating element can also be inserted in place by threading it throughthe casing openings, without the necessity for rotating the outer casingto bring its slot into alignment with the slot in the inner tube.

From the above description, it will be evident that by removing bothterminal caps the heater element can be removed from the casing withoutdisturbing the fusible element, and that the fusible element can beremoved and replaced simply by removing the righth and end cap withoutdisturbing the assembly of the heating element.

In Figs. 9 and 10, a modified construction is shown for the heatingelement. As here shown, the heating element a comprises a flat strip ofresistance material having its ends 62a passed through slots 64a inmetal terminal discs 66a and rcflexed to provide the clamping portions68s as in the previous construction. A flat strip 70a of electricallyinsulating material, as mica, is disposed between the heating element60a. and the fusible element.

In Fig. 11, the cut-out of the invention is shown associated with anelectrically operated switch 80 for controlling the power circuit 58 ofa single phase motor circuit. The switch 80 includes the pairs ofstationary contact members 82 and the bridging or brush members 84therefor which are movable into and out of bridging engagement by asolenoid 86 acting through. a toggle connection 88 with the movablebridging members. Said solenoid 86 includes an energizing coil 90 whichalso constitutes a holding coil. for mainta n ing the breaker releasablyin its circuit clocing position. The heating element 60 of the cut-outembodying the invention is adapted to be heated by the current flow inthe motor circuit 58 and, to this end, the end term nal caps 18 and 20comprising the line terminals of the cutout, are connected in thecircuit 58 so as to include the heating element 60 in series therewith.The fusible element including the linlrs 45 and 46 is connected serieswith the holding coil circuit including the winding 90 of solenoid 86.As thus ar ranged, when an overload flows in the motor circuit 58 ofsufiicient magnitude to heat the offset portions 52 of the fusibleelement and melt the solder 56 constituting the electrical connectiontherebetween, the parts of the fusible element wTll snap apart and thecircuit through the holding coil 90 will be interrupted and the breaker80 will open its circuit. The manual control means 99. including astarting switch 94 and a stopping switch 96 may be provided as iscustomary for controlling the opening and closing of the switch. Thecircuit connections herein shown constitute no part of the presentinvention.

It will be noted that in both constructions herein illustrated thefusible element is disposed alongsi'ie and is closely adjacent theheating element, while the attaching portions 4.8 thereof are locatednear the surface of the casing where they are readily accessible.

Various modifications may be made in the construction and arrangement ofthe parts without departing from the scope of the invention.

I claim.

1. A thermal relay comprising a pair of spaced fixed supports, a thermalelement comprising two sections having their adjacent ends united by afusible material and having their remote ends secured to said supports,and a heater element which is extended along the length of and. close tosaid thermal ele ment and on one side only thereof, one of said sectionsof said thermal element being resilient and being held under stress toits support and adapted to snap away from the cooperating section andalso away from said heater element when said fusible material melts.

2. A thermal relay having an enclosing casing, an electric heatingelement therein, removable discs located at the ends of said casingconstituting supports for the ends of said heating element, removableend caps on said casing holding said discs removably in place, and afusible element located within said casing in heat-receiving relationwith said heating element.

3. A thermal cut-out including an enclosing casing having end terminalmembers, aheating element electrically connecting said terminal members,a fusible element disposed alongside and closely adjacent said heatingelement and electrically connected with one of said end terminalmembers, and an intermediate terminal member carried by said casing andelectrically connected with the other end of said fusible element.

thermal cut-out including a tubular insulating enclosing casing havingend terminal members, a. heating element extended through said casingand electrically connected at its ends with said terminal members, afusible element located substantially in the longitudinal axis of saidcasing alongside and ISO in proximity to said heating element and havingone end thereof electrically connected with an end terminal member ofsaid casing, and an intermediate terminal member carried by said casingand electrically connected with the other end of said fusible element,

5. A thermal cut-out including a tubular enclosing casing having endterminal members and an intermediate erminal member, a heating elementextended through said casing eccentrically thereof and electricallyconnected at its ends with said end terminal members, a fusible elementcentrally disposed within said casing alongside said heating element andhaving one end thereof connected electrically with an end terminalmember of said casing and having its other end electrically connectedwith said intermediate terminal member.

6. A thermal cut-out including an enclosing casing having end terminalmembers, a heating element extended hrough said casing and connectedelectrically with said terminal members, an intermediate terminal membercarried by said casing, and a thermal element comprising two sectionshaving their adjacent ends united-by a fusible material disposedalongside said heating element and having one end thereof connected withan end terminal member of said casing and the other end with saidintermediate terminal, one of said sections of said thermal elementbeing resilient and being held under stress to its cooperating terminaland adapted to snap away from the cooperating section and also away fromsaid heating element when said fusible material melts.

7. A thermal cut-ont including an enclosing insulating shell having endterminal members, a heating element extended through said shell andconnected electrically with said terminal members, an intermediateterminal member carried by said shell, a fusible link disposed in saidcasing alongside said heating element and closely adjacent thereto,means connecting the opposite ends of said link to an end terminalmember and to said intermediate terminal member, said insulating shellhaving provision for the removal of said fusible link through the topthereof.

8. A thermal cutout including a tubular enclosing casing having endterminal members and an intermediate terminal member, a heating elementin said casing extended between and electrically connected with said endterminal members, and a fusible element in said casing extended betweenand electrically connected with an end terminal member and saidintermediate terminal member.

9. A thermal cut-out including a tubular enclosing casing having endterminal members and an intermediate terminal member, a heating elementextended longitudinally through said casing and connected electricallywith said end terminal members, and a fusible element disposed in theaxis of said casing and electrically connecting said intermediateterminal member and one of said end terminal members.

10. A thermal cut-out including a tubular enclosing casing having endterminal members and an intermediate terminal member, a heating elementextended longitudinally through said casing and connected electricallywith said end terminal members, a fusible element disposed in thelongitudinal axis of said casing and electrically connected with saidintermediate terminal member and an end terminal of said casing, saidheating element and fusible element arranged to lie alongside andclosely adjacent each other.

11. A terminal cut-out including a tubular enclosing casing having alongitudinal slot in a side wall thereof, terminal caps removablysecured to the ends of said casing, a third terminal member intermediatesaid end caps, a fusible element disposed in said casing beneath theslots therein and electrically connected at its ends with said thirdterminal and one of said end caps and a heating element extendedlongitudinally through said casing closely adjacent said fusible elementand electrically connected with said end caps.

12. A thermal cut-out including an enclosing casing having alongitudinal slot in a wall thereof, terminal ferrules fixed to the endsof said casing, end caps removably received on said ferrules, a thirdterminal disposed intermediate said terminal ferrules, afusible elementhaving its ends connected electrically to said third terminal and one ofsaid end ferrules, and a heating element ex tended through said casingand secured electrically at its ends with said end caps.

13. A thermal cut-out including an enclosing casing of insulatingmaterial having a longitudinal slot therein, terminal members comprisingline terminals at the ends of said casing, a third terminal membersurrounding said casing intermediate its ends, a fusible elementdisposed in said casing beneath said slot and electrically connectingsaid third terminal and one of said end terminal members, a heatingelement extended longitudinally through said casing and connectedelectrically with the end terminals thereof, said fusible element havinga portion thereof which is parallel with and is closely adj acent saidheating element, and insulating means separating said heating elementand fusible element.

let. A thermal cut-out including a tubular enclosing casing having alongitudinal slot in a wall thereof, terminal ferrules carried by saidcasing atthe ends thereof, one of said ferrules having a slot which iscoincident with the slot in said casing, a terminal block disposed insaid casing having a terminal attach ing portion disposed beneath theslot in said casing, a third terminal disposed exteriorly list of saidcasing intermediate its ends, said third terminal having a peripheralportion which is received Within the slot of said casing and which isprovided with a terminal attaching portion, a fusible element extendedbetween said third terminal and said terminal block and having its endsdetachably secured to the terminal attaching portions thereof, end capsremovably screw threaded on said terminal ferrules, one of said end capsforming a removable closure for the slotted end of said casing, and aheating element extended longitudinally through said casing andconnecting electrically with said end caps.

15. A thermal cut-out including a tubular enclosing casing having alongitudinal slot in a wall thereof, terminal ferrules carried by saidcasing at the ends thereof, one of said ferrules having a slot which iscoincident With the slot in said casing, a terminal block disposed insaid casing having a terminal attaching portion disposed beneath theslot 1n said casing, a third terminal disposed exteriorly of said casingintermediate its ends, said third terminal having a peripheral portionwhich is received within the slot of said casing and which is providedwith a terminal attaching portion, a fusible element extended betweensaid third terminal and said terminal block and having its endsdetachably secured to both, end caps removably screw threaded on saidterminal ferrules, a heating element extended longitudinally throughsaid casing and connecting electrically with said end caps, and atubular outer casing which surrounds and is rotatable on said tubularcasing.

16. A thermal cut-out including a tubular longitudinally-slottedenclosing casing having terminal ferrules at the ends thereof, and anintermediate terminal member having an external thermal seat disposedwithin said casing beneath the slot therein, a terminal block located inthe end of said casing and I electrically connected with an end ferrulethereof having a terminal seat disposed beneath the slot, a fusible linkextended between the terminal seats of said intermediate terminal memberand block having an olfset heat-absorbing portion disposed substantially in the longitudinal axis of said casing, a heating elementextended longitudinally through said casing, a removable cover for theslot in said casing, and terminal caps screw threaded on said ferrulesand separately connected electrically with the opposite ends of saidheating element.

17. A thermal cut-out of the cartridge type including an inner tubularcasing hav- V ing a longitudinal slot therein, terminal ferrules carriedexteriorly of said tube at the ends thereof, one of said ferrules havinga slot coincident with the slot in said casing, a terminal blockdisposed within said tube at the end thereof and electrically connectedwith said slotted ferrule, said terminal block having an upper terminalseat disposed beneath the slot in said casing, a third terminal memberintermediate the ends of said casing comprising a substantially annularband having a flat terminal seat disposed within the casing beneath theslot therein, a fusible link secured removably to the terminal seats ofsaid third terminal member and said terminal block, a heating elementextended longitudinally through said inner tube, end caps comprisingline terminals removably screw threaded on said terminal ferrules andelectrically connected with the ends of said heating element, an outertubular casing closely surrounding said inner tube and rotatable thereonarranged to provide a closure for the slot therein, said outer tubehaving a longitudinal slot therein through which said fusible elementmay be removed when the slot in said outer casing has been rotated toregister with the slot in said inner casing.

18. A thermal cut-out for the pilot circuit of an electrically operatedswitch having the combination. of a tubular enclosing casing, end capsrcmovably located on the ends of the casing constituting line terminalsof the cut-out, an intermediate terminal carried by the casing betweensaid end caps, a fusible element electrically connecting said thirdterminal and one of said end caps, and an outer tubular casing closelysurrounding said inner tube between said third terminal and said end capand freely rotatable thereon, said inner and outer tubular casingshaving longitudinal slots therein through which said fusible element canbe removed when said slots are in superimposed position.

19. A thermal cut-out including an inner tubular shell having alongitudinal slot there in, exteriorily screw threaded metal ferrules onthe ends of said shell, one of said ferrules having a slot which isaligned with the slot in said shell, a terminal ring surrounding saidshell intermediate its ends having a U- shaped peripheral portionthereof extended into said shell through the slot therein and comprisinga terminal engaging seat, a terminal block fixed in the slotted end ofsaid tube having a terminal attaching seat disposed beneath the alignedslots in said tube and ferrule, a fusible element comprising a pair oflinks having one end thereof secured to the terminal seat of said thirdterminal member and contact block respectively and having their otherand abutting ends releasably connected electrically by a fusible metal,terminal caps screw threaded to said ferrules, one of which caps forms aclosure for the slot in said slotted ferrule, an outer insulating tubeclosely surrounding and rotatable on said inner tube between said thirdterminal member and said slotted ferrule having a longitudinal slottherein through which said fusible element is adapted to be removed whenboth slots are aligned, and a heating element extended through saidcasing and connected electrically with said terminal caps.

20. A thermal cut-out including a tubular casing of insulating materialhaving a longitudinal slottherein, terminal members comprising lineterminals of the cut-out fixed to the ends of said casing a thirdterminal member carried by said casing intermediate the ends thereofhaving a U-shaped peripheral portion extended into said casing throughthe slot therein, said U-shaped portion providing a terminal seat, afusible element having a portion thereof disposed in the longitudinalaxis of said casing and having offset attaching portions which aredetachably secured to the seat of said third terminal member and to aline terminal of the cut-out, a heating element extended through saidcasing and electrically connected with said end terminal members, saidheating element arranged to lie closely adjacent the offset portion ofsaid fusible element, and means providing a removable closure for theslot in said inner tubular casing.

21. A thermal cutout including a tubular casing of insulating materialhaving a longitudinal slot therein, terminal members comprising lineterminals of the cut-out fixed to the ends of said casing, a thirdterminal member carried by said casing intermediate the ends thereofhaving a U-shaped peripheral portion extended into said casing throughthe slot therein, said U-shaped portion providing a terminal seat, afusible element; havlng a portion thereof dlsposed 1n the longitudinalaxis of said casing and having offset attaching portions whicharedetachably secured to the seat of said third terminal member and to aline terminal of the cut-out, a heating element extended through saidcasing and electrically connected with said end terminal members, saidheating element arranged to lie closely adjacent the offset portion ofsaid fusible element, and means providing a removable closure for theslot in said inner tubular casing, said means including a concentricouter tubular casing rotatably received on said inner tube and having alongitudinal slot therein arranged to be moved into and out of coveringrelation with the slot in said inner tube, by the rotation thereof.

22. A thermal cut-out of the cartridge type including the combination ofan inner tubular insulating shell having a longitudinal slot therein,terminal ferrules surrounding and fixed to the ends of said shell, oneof said ferrules having a slot therein coincident with the slot in theshell, a terminal block disposed beneath the slot in said ferrule havingterminal attaching means disposed beneath said slot, an intermediateterminal member carried externally by said shell comprisingasubstantially annular member having a de pressed peripheral portionthereof extended through the slot in said shell and having terminalattaching means beneath the open slot therein, terminal caps removablyscrew threaded on said terminal ferrules, one of said caps constitutinga closure for the slot in said slotted ferrule, terminal washersdisposed within said terminal caps having passages therethrough, aheating element extended longitudinally through said shell having itsterminals extended through said passages and reflexed along the outerfaces of. said terminal washers, and a fusible element located alongsideand closely adjacent said ieating element beneath the slot in said shelland having its terminals removably secured beneath the terminalattaching means of said third terminal member and said terminal block,whereby to permit removal of said fusible element through the slottedside wall of said shell.

23. A thermal cut-out of the cartridge type including the combination ofan inner tubular insulating shell having a longitudinal slot therein,terminal ferrules surrounding and fixed to the ends of said shell, oneof said ferrules having a slot therein coincident with the slot in theshell, a terminal block disposed beneath the slot in said ferrule havingterminal attaching means disposed beneath said slot, an intermediateterminal member carried externally by said shell comprising asubstantially annular member having exposed terminal attaching meansbeneath the open slot therein, terminal caps removably screw threaded onsaid terminal ferrules, one of said caps constituting a closure for theslot in said slotted ferrule, terminal washers disposed within saidterminal caps having passages therethrough, a heating element extendedlongitudinally through said shell having its terminals extended throughsaid passages and reflexed along the outer faces of said terminalwashers, and a fusible element electrically connecting said thirdterminal and terminal block comprising a pair of links having horizontalattaching portions which are secured removably to said third terminaland terminal block respectively by the attaching means thereof, andhaving offset abutting heat-absorbing portions which are releasablyconnected elect "ically together by a fusible mass, one of said linkshaving its attaching portion refiexed whereby to bias the offset portionthereof constantly into a position free from its abutting cooperatinglink.

24. A thermal cut-out including an insulating enclosing shell having atop opening at one end thereof, screw threaded terminal members carriedby the ends thereof, one of said terminal members arranged to form aclosure for said: top opening, a heating element extended through saidcasing and connected electrically at its ends with said terminalmembers, an intermediate terminal mem her having a top portion thereofextended downwardly within said insulating shell, a fusible linlrdisposed within said shell alongside said heating element andelectrically con nected at one end with said intermediate terminalmember, terminal block fixed in said shell beneath said top opening andelectrically connected with an end terminal thereof, and meansaccessible through said top opening for attachin the free end of saidfusible element to said terminal block. 7

25. A thermal cut-out including a tubular insulating shell having a topopening at one end thereof, end terminal members screw threaded to saidshell, one of said terminal members forming a closure for said topopening, an intermediate ter ninal member carried by said shell having aperipheral portion thereof extended downwardly within said shell toprovide an externally exposed terminal seat, a terminal block having aterminal seat disposed within said shell beneath said top opening andelectrically connected with an end terminal of said shell, a fusiblelink extended between the terminal seats of said intermediate terminalmember and said terminal block, terminal engaging means to se cure said.fusible link releasably in the aforesaid position, and a heating elementdisposed in said shell alongside said fusible linlz.

In testimony whereof, I have signed my name to this specification.

GEORGE W. OKEEFFE.

Nov. 1, 1932. A. B. SALIGER 1,886,358

AUTOMATIC TIME CONTRCLLED SUGGESTION MACHINE Filed Oct. 20. 1928f/'ig.1.

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